Cobalt(II), silver(I), and lead(II) tetrabromoterephthalates exhibiting the 1-D linear chain, 2-D CdCl 2-type layer, and 3-D penta-nodal mixed-connecting coordination frameworks

Abstract

Reaction of tetrabromoterephthalic acid (H 2TBTA) with Co(OAc) 2, AgNO 3, or Pb(OAc) 2 under similar conditions affords three new coordination polymers {[Co(TBTA)(DMF) 2(H 2O) 2](DMF) 2} n ( 1), [Ag(TBTA) 0.5] n ( 2), and [Pb 2(TBTA) 1.5(OH)(DMF)] n ( 3). All these complexes have been characterized by elemental analysis, IR, powder X-ray diffraction, and TG-DTA techniques. Single-crystal X-ray diffraction reveals that complex 1 has a 1-D neutral coordination array in which the adjacent Co II centers are bridged by the TBTA spacers, whereas 2 displays a binodal CdCl 2-type coordination layer in which the Ag I ions and TBTA ligands function as 3- and 6-connected nodes, respectively. In the structure of 3, two types of Pb II ions are interconnected via the μ 4- and μ 5-TBTA ligands as well as the μ 3-hydroxyl ions to generate a complicated 3-D penta-nodal coordination framework with (3,4,5)-connectivity. These results clearly suggest that the metal centers with distinct binding tendencies are responsible for the remarkable structural diversity of such crystalline materials.